Average Fetal Length and Weight Chart
From eight to approximately 20 weeks, your baby will be measured from crown to
rump as below:
| Pregnancy week
| Length (inches)
| Weight (ounces)
| Length (cm)
| Mass (g)
|
| 8 weeks |
0.63 inch |
0.04 ounce |
1.6 cm |
1 gram |
| 9 weeks |
0.90 inch |
0.07 ounce |
2.3 cm |
2 grams |
| 10 weeks |
1.22 inch |
0.14 ounce |
3.1 cm |
4 grams |
| 11 weeks |
1.61 inch |
0.25 ounce |
4.1 cm |
7 grams |
| 12 weeks |
2.13 inches |
0.49 ounce |
5.4 cm |
14 grams |
| 13 weeks |
2.91 inches |
0.81 ounce |
7.4 cm |
23 grams |
| 14 weeks |
3.42 inches |
1.52 ounce |
8.7 cm |
43 grams |
| 15 weeks |
3.98 inches |
2.47 ounces |
10.1 cm |
70 grams |
| 16 weeks |
4.57 inches |
3.53 ounces |
11.6 cm |
100 grams |
| 17 weeks |
5.12 inches |
4.94 ounces |
13 cm |
140 grams |
| 18 weeks |
5.59 inches |
6.70 ounces |
14.2 cm |
190 grams |
| 19 weeks |
6.02 inches |
8.47 ounces |
15.3 cm |
240 grams |
| 20 weeks |
6.46 inches |
10.58 ounces |
16.4 cm |
300 grams |
Then from approximately 20 weeks, your baby will be measured from crown to heel:
|
20 weeks |
10.08 inches |
10.58 ounces |
25.6 cm |
300 grams |
|
21 weeks |
10.51 inches |
12.70 ounces |
26.7 cm |
360 grams |
|
22 weeks |
10.94 inches |
15.17 ounces |
27.8 cm |
430 grams |
|
23 weeks |
11.38 inches |
1.10 pound |
28.9 cm |
501 grams |
|
24 weeks |
11.81 inches |
1.32 pound |
30 cm |
600 grams |
|
25 weeks |
13.62 inches |
1.46 pound |
34.6 cm |
660 grams |
|
26 weeks |
14.02 inches |
1.68 pound |
35.6 cm |
760 grams |
|
27 weeks |
14.41 inches |
1.93 pound |
36.6 cm |
875 grams |
|
28 weeks |
14.80 inches |
2.22 pounds |
37.6 cm |
1005 grams |
|
29 weeks |
15.2 inches |
2.54 pounds |
38.6 cm |
1153 grams |
|
30 weeks |
15.71 inches |
2.91 pounds |
39.9 cm |
1319 grams |
|
31 weeks |
16.18 inches |
3.31 pounds |
41.1 cm |
1502 grams |
|
32 weeks |
16.69 inches |
3.75 pounds |
42.4 cm |
1702 grams |
|
33 weeks |
17.20 inches |
4.23 pounds |
43.7 cm |
1918 grams |
|
34 weeks |
17.72 inches |
4.73 pounds |
45 cm |
2146 grams |
|
35 weeks |
18.19 inches |
5.25 pounds |
46.2 cm |
2383 grams |
|
36 weeks |
18.66 inches |
5.78 pounds |
47.4 cm |
2622 grams |
|
37 weeks
|
19.13 inches |
6.30 pounds |
48.6 cm |
2859 grams |
|
38 weeks |
19.61 inches |
6.80 pounds |
49.8 cm |
3083 grams |
|
39 weeks |
19.96 inches |
7.25 pounds |
50.7 cm |
3288 grams |
|
40 weeks |
20.16 inches |
7.63 pounds |
51.2 cm |
3462 grams |
|
41 weeks |
20.35 inches |
7.93 pounds |
51.7 cm |
3597 grams |
|
42 weeks |
20.28 inches |
8.12 pounds |
51.5 cm |
3685 grams |
|
43 weeks |
20.20 inches |
8.19 pounds |
51.3 cm |
3717 grams |
Sources:
Doublet PM, Benson CB, Nadel AS, et al: "Improved birth weight table for
neonates developed from gestations dated by early ultrasonography." Journal of
Ultrasound Medicine. 16:241, 1997.
Hadlock FP, Shah YP, Kanon DJ, et al. "Fetal crown rump length: Reevaluation of
relation to menstrual age with high resolution real-time US Radiology." 182:501,
1992.
Usher R, McLean F. "Intrauterine growth of live-born Caucasian infants at sea
level: Standards obtained from measurements in 7 dimensions of infants born
between 25 and 44 weeks of gestation." Pediatrics. v.74, 1969.
Wigglesworth JS. Perinatal Pathology, Second Edition. W.B. Saunders Company.
1996. page 24.